Technical Field
The present disclosure relates to surgical retraction, and more particularly, to a minimally invasive retractor for spine surgery, including lateral access surgery.
Background of Related Art
In connection with surgery on the human spine, accessing the spine may be difficult and complex, and traditional open access through many layers of soft tissue contributes to post surgery pain and discomfort, and may prolong recovery and impede favorable results of surgery.
Attempts have been made to make retractors which provide less disruptive access through soft tissue to reach the spine. Examples include Hamada U.S. Pat. Nos. 6,849,064; 7,318,817; 7,883,522; 7,935,054; 7,887,482 all entitled “Minimal Access Lumbar Diskectomy Instrumentation and Method”, and Hamada U.S. Pat. Nos. 7,850,608; 7,946,982; 8,636,657; 8,298,139; and 8,303,499 all entitled “Minimal Incision Maximal Access MIS Spine Instrumentation and Method”, all of which are incorporated herein by reference.
In so-called lateral access or trans-psoas muscle spine surgery the spine is approached from a lateral direction, from the side of the patient. In this approach, access typically must be gained through the psoas muscle in order to reach the spine. Retractors used for such lateral access surgery include the Maximum Access Surgery (MAS®) platform from Nuvasive, Inc. (San Diego, Calif.), the MARS™3V system from Globus Medical, Inc. (Audubon, Pa.), the Pipeline LS from Depuy Synthes Spine (Raynam, Mass.) and the Direct Lateral Interbody Fusion (DLIF) system from Medtronic Sofamor Danek (Memphis, Tenn.). The following patents and published patent applications may show or describe these commercially available systems. Arambula U.S. Pat. No. 7,785,253 entitled “Surgical Access System and Related Methods”; Wooley U.S. Pat. No. 8,535,320 entitled “Method and Apparatus for Performing Spinal Surgery”; Miles U.S. Published Patent Applications 2014/0180016 and 2014/0288375, both entitled “Surgical Access System and Related Methods”; Pimenta U.S. Pat. No. 8,827,900 entitled “Surgical Access System and Related Methods”; Frasier U.S. Pat. No. 8,550,995 entitled “Surgical Access Devices and Methods of Minimally Invasive Surgery”; Karpowicz U.S. Pat. No. 7,935,053 entitled “Surgical Retractor System”; and Weiman U.S. Pat. No. 8,353,826 entitled “Tissue Retractor and Method of Use”. The foregoing patents and applications are incorporated herein by reference.
The foregoing lateral access systems typically use a plurality of sequentially dilating cannulas of increasing outer diameter inserted one over another to create an initial access path to the spine. Once the last dilating cannula is in place, a retractor assembly is inserted over the dilating cannula, and is operated to move the retractor blades apart in a generally radial direction to spread soft tissue and create a working path to the spine. Sequentially dilating cannulas, followed by radial retraction is not an efficient means to create a working path to the spine, and spreading the soft tissue and the psoas muscle in this manner is more traumatic to the tissue than necessary, and may prolong recovery.
The Ravine® retractor system available from K2M, Inc. (Leesburg, Va.) is a substantial improvement in lateral spinal access retraction. The Ravine retractor system and method of use are described in Nunley U.S. Pat. No. 8,449,463 entitled “Lateral Access System and Methods of Use”, which is incorporated herein by reference. In the Ravine system, the retractor has two slim profile blades that are inserted through soft tissue over a previously placed pin or wire with the retractor blades aligned with the fibers of the psoas muscle. The retractor blades pass between the fibers of the muscle with reduced trauma to the muscle, and without any need for sequentially dilating cannulas. Once the Ravine retractor is inserted, it is rotated ninety degrees to orient the blades transverse to the psoas muscle. The retractor blades are then spread apart to retract tissue and create a working path to the spine. While the Ravine system is a significant improvement over other lateral access retractors, a degree of trauma, albeit less than with other retractors, is introduced by rotating the retractor blades ninety degrees to split the psoas muscle, and then spreading the retractor blades apart.
Thus, a need exists for an improved retractor system to access the spine with minimal trauma to soft tissue.